AVER Media makes a hybrid tuner that has ATSC and NTSC tuners in one.
First, you need to find out what kind of signal is in the wire.
If the service is from AT&T, which I think only does U-Verse, then it is IPTV and SOL, since there is nothing at this point that can do IPTV. Microsoft hinted that the new XBOX may be able to work with IPTV.
What you have picked up may have been the OTA channels that were picked up by the wire, as if it were an antenna.
Most commercial cable companies do local broadcast channels, the ones you can pick up with an antenna over QAM, and the encrypt everything else. Some offer analog channels, still, but it is not going to last forever.
The only tuner that I can think of, that can do NTSC, ATSC, QAM, and Encrypted Cable is ATI Digital Cable Tuner.
6 TV's in the house on FiOS and we only pay $4.99/month to connect them all!!! Power to the CableCard and WMC7!!!